Pink Floyd - echoes segment one, 1970

"Echoes" is a song by the English rock band Pink Floyd, and the sixth and last track on their 1971 album Meddle. It is 23+1⁄2 minutes long, the second longest of their discography, eight seconds shorter than Atom Heart Mother Suite, and takes up the entire second side of the original LP. The track evolved from a variety of different musical themes and ideas, including instrumental passages and studio effects, resulting in the side-long piece. The music, credited to all the band, was mainly written by Richard Wright and David Gilmour, while Roger Waters' lyrics addressed themes of human communication and empathy, to which he returned in later work."